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How to check if a character is alphanumeric in Java with if-else
okwudili onyejiaku
Overview
Without any inbuilt method, we can check if a given character is alphanumeric or not. An alphanumeric character is a character that is either a number or an alphabet. The logic to find out if a character is alphanumeric is listed below:
- Is the character greater than or equal to
'0'and less than or equal to9? - Or is the character greater than or equal to
aand less than or equal toz? - Or is the character greater than or equal to
Aand less than or equal toZ?
We can see if a character is an alphanumeric character with these given conditions above.
Syntax
if ((character >= '0' && character <= '9') || (character >= 'a' && character <= 'z') || (character >= 'A' && character <= 'Z')){
// character is alphanumeric
}else{
// character is not alphanumeric
}Syntax to check if a character is alphanumeric in Java without an inbuilt method
Parameters
character: This is the character we want to check if it is alphanumeric or not.
Example
class HelloWorld {
// create function to check if alphanumeric
static void checkIfAlphanumeric(char character){
if ((character >= '0' & character <= '9') || (character >= 'a' && character <= 'z') || (character >= 'A' && character <= 'Z')){
System.out.println(character +" is alphanumeric");
}else{
System.out.println(character +" is not alphanumeric");
}
}
public static void main( String args[] ) {
// check if some characters are alphanumeric
checkIfAlphanumeric('e');
checkIfAlphanumeric('1');
checkIfAlphanumeric('r');
checkIfAlphanumeric('%');
checkIfAlphanumeric(',');
}
}Check if a character is alphanumeric in Java
Explanation
- Line 3: We create a function to check if a character is alphanumeric. It takes a character as a parameter and applies the condition discussed above.
- Lines 12–16: We check if some characters are alphanumeric with the function we created.
RELATED TAGS
java
character
alphanumeric
if else
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CONTRIBUTOR
okwudili onyejiaku
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